CEMC Pascal, 2007

Combinatorics Difficulty 3.0 AMC 10/12 Find the answer Canada

Clara knocks over the two stacks of blocks shown in the diagram. She then uses the blocks to build a similar stack whose top layer has one block and each layer below has one more block than the layer above it. If she builds the largest possible stack, how many blocks will be left over?

(A) $0$ (B) $1$ (C) $2$ (D) $3$ (E) $4$

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